package com.flycent.hqhs.ui.view;
import java.util.ArrayList;

import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.content.Context;
import android.database.DataSetObservable;
import android.database.DataSetObserver;
import android.os.Build;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.Filter;
import android.widget.Filterable;
import android.widget.FrameLayout;
import android.widget.GridView;
import android.widget.ListAdapter;
import android.widget.WrapperListAdapter;

/**
 * @author fbl
 *   自定义GridView 实现GridView 添加hearderView 和 footView 
 */
@TargetApi(Build.VERSION_CODES.HONEYCOMB) 
public class HeaderGridView extends GridView {
	
	/**
	 * A class that represents a fixed view in a list, for example a header at the top
	 * or a footer at the bottom.
	 */
	private static class FixedViewInfo {
		/** The view to add to the grid */
		public View view;
		public ViewGroup viewContainer;
		/** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */
		public Object data;
		/** <code>true</code> if the fixed view should be selectable in the grid */
		public boolean isSelectable;
	}
	private ArrayList<FixedViewInfo> mHeaderViewInfos = new ArrayList<FixedViewInfo>();
	private void initHeaderGridView() {
		super.setClipChildren(false);
	}
	public HeaderGridView(Context context) {
		super(context);
		initHeaderGridView();
	}
	public HeaderGridView(Context context, AttributeSet attrs) {
		super(context, attrs);
		initHeaderGridView();
	}
	public HeaderGridView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		initHeaderGridView();
	}
	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		super.onMeasure(widthMeasureSpec, heightMeasureSpec);
		ListAdapter adapter = getAdapter();
		if (adapter != null && adapter instanceof HeaderViewGridAdapter) {
			((HeaderViewGridAdapter) adapter).setNumColumns(getNumColumns());
		}
	}
	@Override
	public void setClipChildren(boolean clipChildren) {
		// Ignore, since the header rows depend on not being clipped
	}
	/**
	 * Add a fixed view to appear at the top of the grid. If addHeaderView is
	 * called more than once, the views will appear in the order they were
	 * added. Views added using this call can take focus if they want.
	 * <p>
	 * NOTE: Call this before calling setAdapter. This is so HeaderGridView can wrap
	 * the supplied cursor with one that will also account for header views.
	 *
	 * @param v The view to add.
	 * @param data Data to associate with this view
	 * @param isSelectable whether the item is selectable
	 */
	public void addHeaderView(View v, Object data, boolean isSelectable) {
		ListAdapter adapter = getAdapter();
		if (adapter != null && ! (adapter instanceof HeaderViewGridAdapter)) {
			throw new IllegalStateException(
					"Cannot add header view to grid -- setAdapter has already been called.");
		}
		FixedViewInfo info = new FixedViewInfo();
		FrameLayout fl = new FullWidthFixedViewLayout(getContext());
		fl.addView(v);
		info.view = v;
		info.viewContainer = fl;
		info.data = data;
		info.isSelectable = isSelectable;
		mHeaderViewInfos.add(info);
		// in the case of re-adding a header view, or adding one later on,
		// we need to notify the observer
		if (adapter != null) {
			((HeaderViewGridAdapter) adapter).notifyDataSetChanged();
		}
	}
	/**
	 * Add a fixed view to appear at the top of the grid. If addHeaderView is
	 * called more than once, the views will appear in the order they were
	 * added. Views added using this call can take focus if they want.
	 * <p>
	 * NOTE: Call this before calling setAdapter. This is so HeaderGridView can wrap
	 * the supplied cursor with one that will also account for header views.
	 *
	 * @param v The view to add.
	 */
	public void addHeaderView(View v) {
		addHeaderView(v, null, true);
	}
	public int getHeaderViewCount() {
		return mHeaderViewInfos.size();
	}
	/**
	 * Removes a previously-added header view.
	 *
	 * @param v The view to remove
	 * @return true if the view was removed, false if the view was not a header
	 *         view
	 */
	public boolean removeHeaderView(View v) {
		if (mHeaderViewInfos.size() > 0) {
			boolean result = false;
			ListAdapter adapter = getAdapter();
			if (adapter != null && ((HeaderViewGridAdapter) adapter).removeHeader(v)) {
				result = true;
			}
			removeFixedViewInfo(v, mHeaderViewInfos);
			return result;
		}
		return false;
	}
	private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) {
		int len = where.size();
		for (int i = 0; i < len; ++i) {
			FixedViewInfo info = where.get(i);
			if (info.view == v) {
				where.remove(i);
				break;
			}
		}
	}
	@SuppressLint("NewApi") @Override
	public void setAdapter(ListAdapter adapter) {
		if (mHeaderViewInfos.size() > 0) {
			HeaderViewGridAdapter hadapter = new HeaderViewGridAdapter(mHeaderViewInfos, adapter);
			int numColumns = getNumColumns();
			if (numColumns > 1) {
				hadapter.setNumColumns(numColumns);
			}
			super.setAdapter(hadapter);
		} else {
			super.setAdapter(adapter);
		}
	}
	private class FullWidthFixedViewLayout extends FrameLayout {
		public FullWidthFixedViewLayout(Context context) {
			super(context);
		}
		@Override
		protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
			int targetWidth = HeaderGridView.this.getMeasuredWidth()
					- HeaderGridView.this.getPaddingLeft()
					- HeaderGridView.this.getPaddingRight();
			widthMeasureSpec = MeasureSpec.makeMeasureSpec(targetWidth,
					MeasureSpec.getMode(widthMeasureSpec));
			super.onMeasure(widthMeasureSpec, heightMeasureSpec);
		}
	}
	/**
	 * ListAdapter used when a HeaderGridView has header views. This ListAdapter
	 * wraps another one and also keeps track of the header views and their
	 * associated data objects.
	 *<p>This is intended as a base class; you will probably not need to
	 * use this class directly in your own code.
	 */
	private static class HeaderViewGridAdapter implements WrapperListAdapter, Filterable {
		// This is used to notify the container of updates relating to number of columns
		// or headers changing, which changes the number of placeholders needed
		private final DataSetObservable mDataSetObservable = new DataSetObservable();
		private final ListAdapter mAdapter;
		private int mNumColumns = 1;
		// This ArrayList is assumed to NOT be null.
		ArrayList<FixedViewInfo> mHeaderViewInfos;
		boolean mAreAllFixedViewsSelectable;
		private final boolean mIsFilterable;
		public HeaderViewGridAdapter(ArrayList<FixedViewInfo> headerViewInfos, ListAdapter adapter) {
			mAdapter = adapter;
			mIsFilterable = adapter instanceof Filterable;
			if (headerViewInfos == null) {
				throw new IllegalArgumentException("headerViewInfos cannot be null");
			}
			mHeaderViewInfos = headerViewInfos;
			mAreAllFixedViewsSelectable = areAllListInfosSelectable(mHeaderViewInfos);
		}
		public int getHeadersCount() {
			return mHeaderViewInfos.size();
		}
		@Override
		public boolean isEmpty() {
			return (mAdapter == null || mAdapter.isEmpty()) && getHeadersCount() == 0;
		}
		public void setNumColumns(int numColumns) {
			if (numColumns < 1) {
				throw new IllegalArgumentException("Number of columns must be 1 or more");
			}
			if (mNumColumns != numColumns) {
				mNumColumns = numColumns;
				notifyDataSetChanged();
			}
		}
		private boolean areAllListInfosSelectable(ArrayList<FixedViewInfo> infos) {
			if (infos != null) {
				for (FixedViewInfo info : infos) {
					if (!info.isSelectable) {
						return false;
					}
				}
			}
			return true;
		}
		public boolean removeHeader(View v) {
			for (int i = 0; i < mHeaderViewInfos.size(); i++) {
				FixedViewInfo info = mHeaderViewInfos.get(i);
				if (info.view == v) {
					mHeaderViewInfos.remove(i);
					mAreAllFixedViewsSelectable = areAllListInfosSelectable(mHeaderViewInfos);
					mDataSetObservable.notifyChanged();
					return true;
				}
			}
			return false;
		}
		@Override
		public int getCount() {
			if (mAdapter != null) {
				return getHeadersCount() * mNumColumns + mAdapter.getCount();
			} else {
				return getHeadersCount() * mNumColumns;
			}
		}
		@Override
		public boolean areAllItemsEnabled() {
			if (mAdapter != null) {
				return mAreAllFixedViewsSelectable && mAdapter.areAllItemsEnabled();
			} else {
				return true;
			}
		}
		@Override
		public boolean isEnabled(int position) {
			// Header (negative positions will throw an ArrayIndexOutOfBoundsException)
			int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns;
			if (position < numHeadersAndPlaceholders) {
				return (position % mNumColumns == 0)
						&& mHeaderViewInfos.get(position / mNumColumns).isSelectable;
			}
			// Adapter
			final int adjPosition = position - numHeadersAndPlaceholders;
			int adapterCount = 0;
			if (mAdapter != null) {
				adapterCount = mAdapter.getCount();
				if (adjPosition < adapterCount) {
					return mAdapter.isEnabled(adjPosition);
				}
			}
			throw new ArrayIndexOutOfBoundsException(position);
		}
		@Override
		public Object getItem(int position) {
			// Header (negative positions will throw an ArrayIndexOutOfBoundsException)
			int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns;
			if (position < numHeadersAndPlaceholders) {
				if (position % mNumColumns == 0) {
					return mHeaderViewInfos.get(position / mNumColumns).data;
				}
				return null;
			}
			// Adapter
			final int adjPosition = position - numHeadersAndPlaceholders;
			int adapterCount = 0;
			if (mAdapter != null) {
				adapterCount = mAdapter.getCount();
				if (adjPosition < adapterCount) {
					return mAdapter.getItem(adjPosition);
				}
			}
			throw new ArrayIndexOutOfBoundsException(position);
		}
		@Override
		public long getItemId(int position) {
			int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns;
			if (mAdapter != null && position >= numHeadersAndPlaceholders) {
				int adjPosition = position - numHeadersAndPlaceholders;
				int adapterCount = mAdapter.getCount();
				if (adjPosition < adapterCount) {
					return mAdapter.getItemId(adjPosition);
				}
			}
			return -1;
		}
		@Override
		public boolean hasStableIds() {
			if (mAdapter != null) {
				return mAdapter.hasStableIds();
			}
			return false;
		}
		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
			// Header (negative positions will throw an ArrayIndexOutOfBoundsException)
			int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns ;
			if (position < numHeadersAndPlaceholders) {
				View headerViewContainer = mHeaderViewInfos
						.get(position / mNumColumns).viewContainer;
				if (position % mNumColumns == 0) {
					return headerViewContainer;
				} else {
					if (convertView == null) {
						convertView = new View(parent.getContext());
					}
					// We need to do this because GridView uses the height of the last item
					// in a row to determine the height for the entire row.
					convertView.setVisibility(View.INVISIBLE);
					convertView.setMinimumHeight(headerViewContainer.getHeight());
					return convertView;
				}
			}
			// Adapter
			final int adjPosition = position - numHeadersAndPlaceholders;
			int adapterCount = 0;
			if (mAdapter != null) {
				adapterCount = mAdapter.getCount();
				if (adjPosition < adapterCount) {
					return mAdapter.getView(adjPosition, convertView, parent);
				}
			}
			throw new ArrayIndexOutOfBoundsException(position);
		}
		@Override
		public int getItemViewType(int position) {
			int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns;
			if (position < numHeadersAndPlaceholders && (position % mNumColumns != 0)) {
				// Placeholders get the last view type number
				return mAdapter != null ? mAdapter.getViewTypeCount() : 1;
			}
			if (mAdapter != null && position >= numHeadersAndPlaceholders) {
				int adjPosition = position - numHeadersAndPlaceholders;
				int adapterCount = mAdapter.getCount();
				if (adjPosition < adapterCount) {
					return mAdapter.getItemViewType(adjPosition);
				}
			}
			return AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER;
		}
		@Override
		public int getViewTypeCount() {
			if (mAdapter != null) {
				return mAdapter.getViewTypeCount() + 1;
			}
			return 2;
		}
		@Override
		public void registerDataSetObserver(DataSetObserver observer) {
			mDataSetObservable.registerObserver(observer);
			if (mAdapter != null) {
				mAdapter.registerDataSetObserver(observer);
			}
		}
		@Override
		public void unregisterDataSetObserver(DataSetObserver observer) {
			mDataSetObservable.unregisterObserver(observer);
			if (mAdapter != null) {
				mAdapter.unregisterDataSetObserver(observer);
			}
		}
		@Override
		public Filter getFilter() {
			if (mIsFilterable) {
				return ((Filterable) mAdapter).getFilter();
			}
			return null;
		}
		@Override
		public ListAdapter getWrappedAdapter() {
			return mAdapter;
		}
		public void notifyDataSetChanged() {
			mDataSetObservable.notifyChanged();
		}
	}
}
